Remove environment variables from logs only if they are in the requests

radicale/__init__.py

@@ -113,6 +113,7 @@ class Application(object):
         """Remove environment variables from the headers for logging."""
         request_environ = dict(environ)
         for shell_variable in os.environ:
+            if shell_variable in request_environ:
                 del request_environ[shell_variable]
         return request_environ
     # pylint: enable=E0202